Ignition distributors



March 17, 1970 w. H. cooKsEY IGNITION DISTRIBUTORS 2 Sheets-Sheet 1 Filed Feb. 26, 1968 VIA/7%? 4%.. g 3

March 17, 1970 w. H. COOKSEY 3,501,501

IGNITION DISTRIBUTORS I Filed Feb. 26, 1968 2 Sheets-Sheet I fact/4 United States Patent 3,501,601 IGNITION DISTRIBUTORS William Harold Cooksey, Walsall, England, assignor to Joseph Lucas (Industries) Limited Filed Feb. 26, 1968, Ser. No. 708,353 Claims priority, application Great Britain, Mar. 6, 1967, 10,421/ 67 Int. Cl. H01h 19/62 US. Cl. 200-30 3 Claims ABSTRACT OF THE DISCLOSURE An ignition distributor for use in a road vehicle includes a casing having a cam shaft mounted for rotation therein. A first plate is fixed Within the casing and a sleeve surrounds, and is spaced from the camshaft. Second and third plates are engaged with the sleeve so that the second and thirdplates are parallel with the first plate, and the third plate is angularly movable with respect to the second plate about the axis of the sleeve. Means are provided ,,interconnecting the first and second plates for relative angular movement about an axis offset from the axis of the shaft, and a contact breaker assembly in-' cluding a'fixed contact and a movable contact is carried by the third plate. The arrangement is such that angular movement of the second plate with respect to the first plate acts through the sleeve to move the third plate in a direction to move the contact breaker assembly towards or away from the camshaft so as to adjust the contact gap. Moreover, angular movement of the third plate with respect to the second plate moves the contact breaker assembly angularly with respect to the camshaft to adjust the ignition timing of the distributor.

This invention relates to ignition distributors for use in road vehicles.

An ignition distributor according to the invention includes a casing, a camshaft rotatable within the casing, a first plate fixed within the casing, a sleeve surrounding and spaced from the camshaft, second and third plates engaged with the sleeve so that the second and third plates are parallel with the first plate, and the third plate is angularly movable with respect to the second plate about the axis of the sleeve, means interconnecting the first and second plates for relative angular movement about an axis offset from the axis of the shaft, and a contact breaker assembly, including a fixed contact and a movable contact, carried by the third plate, the arrangement being such that angular movement of the second plate with respect to the first plate acts through the sleeve to move the third plate in a direction to move the contact breaker assembly towards or away from the camshaft to adjust the contact gap, and angular movement of the third plate with respect to the second plate moves the contact breaker assembly angularly with respect to the camshaft to adjust the ignition timing of the distributor.

One example of the invention is illustrated in the accompanying drawings wherein: I

FIGURE 1 is a plan view of a distributor with parts thereof omitted for clarity, and

FIGURE 2 is a composite sectional view of the distributor shown, in FIGURE 1 showing also the parts omitted from FIGURE 1.

Referring to the drawings, the distributor includes a cylindrical casing 11 having an axially extending cam shaft 12 journalled for rotation therein. Secured within the casing and surrounding the shaft 12 is a first annular plate 13. A second plate 14 is pivotally engaged with the plate 13 by means of a pin 15, the plate 14 lying in facial contact with the lower surface of the plate 13. The plate ice 14 has a central plunged hole 16 therein and the plates 13, 14 are so arranged that the short cylindrical axial flange 17 defined by the plunged hole 16 in the plate 14 extends through the central hole 13a of the plate 13, the diameters of the hole 13a and the flange 17 being such that a clearance gap is defined between them.

Slidably mounted on the plate 13 is an annular timing plate 18. The plate 18 is pivotally engaged with the plate 14 by means of a sleeve 19 which is secured at its upper end to the plate 18 and which passes through the central holes in the plates 13, 14. The lower end of the sleeve 19 is engaged as a sliding fit in the flange 17 of the plate 14. An annular disc spring 21 is secured to the free end of the sleeve 19, the periphery of the spring 21 engaging the lower surface of the plate 14 and serving to urge the plates 14, 18 towards one another and into engagement with the plate 13. The plate 18 is provided with slippers 20 which bear against the plate 13 to reduce friction.

Upstanding from the plate 18 is a lug 22 having secured thereto a fixed contact 23. Moreover, also upstanding from the plate 18 is a pivot post 24 with which an insulating cam follower 25 is pivotally engaged. The cam follower 25 carries a movable contact 26. One end of a leaf spring 27 is secured to the cam follower while its other end is secured to and insulated from a further post 28 upstanding from the plate 18. The spring 27 is electrically connected to the contact 26 and serves to urge the contact 26 into engagement with the contact 23. The arrangement is such that rotation of the camshaft 12 effects movement of the contact 26 towards and away from the contact 23. The push rod 29 of a known vacuum advance unit associated with the distributor is pivotally engaged with a pin 30 which extends downwardly from the plate 18 so that movements of the rod 29 pivots the plate 18 with respect to the plate 14 about the axis of the sleeve 19, thereby altering the angular position of the cam follower 25 with respect to the shaft 12 to adjust the ignition timing of the distributor.

Extending downwardly from the periphery of the plate 14 is a lug 31 having therein a screw threaded hole. The lug 31 is engaged by a screw 32 which extends through a clearance hole in the casing 11 of the distributor, a compression spring 33 being interposed between the lug 31 and the casing 11 and surrounding the screw 32. The head of the screw 32 is larger than the clearance hole in the casing 11 so that as the screw 32 is rotated the plate 14 is caused to pivot about the pin 15. Pivotal movement of the plate 14 about the pin 15 moves the sleeve 19 and the plate 18 on an arc struck from the pin 15 and so rotation of the screw 32 will move the cam follower 25 towards or away from the cam shaft 12 so as to alter the gap between the contact 26 and the contact 23.

In use, where the distributor is used in a known conventional ignition system, the contact 23 is earthed through the plate 18 and a lead 34 connected to the casing and the contact 26 is connected through the spring 27 and the primary winding of an ignition coil to a DC. supply. Thus rotation of the camshaft 12 makes and breaks the electrical circuit to the primary winding of the ignition coil. However, the distributor is primarily intended for use with an electronic ignition system in which a spark is produced at both the make and break of a contact breaker. Such a system enables a distributor having a four-lobe camshaft to be used to control an eight-cylinder engine, but it will be appreciated that if the engine is to run smoothly the makes and breaks must be spaced apart by even intervals. In order to use the distributor shown in the drawings in such an ignition system, the plate 18 is adjusted to position the sleeve 19 substantially concentric with the shaft 12 so that 3. angular movements of the plate 18 do not move the cam follower 25 substantially towards or away from the shaft 12. The dimensions of the cam follower and the contact gap are calculated with respect to a particular cam form so that when the distributor is set by rotating the screw 32 to 'move the sleeve 19 to a position substantially concentric with the shaft 12, the contact gap will be such as to give equal spacing between the make and break of the contact breaker. In order to compensate for wear at the contacts and at the cam follower 25, the setting of the distributor is adjusted from time to time using the screw 32.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An ignition distributor including a casing, a camshaft mounted for rotation within the casing, a first plate fixed within the casing and through which the camshaft extends, a second plate, positioned parallel to the first plate, pivot means pivotally interconnecting the second plate and the first plate, said pivot means being olfset from the axis of the camshaft, so that said second plate is pivotable relative to said first plate about an axis offset from the axis of the camshaft, a third plate, positioned within the casing, a sleeve surrounding and spaced from the camshaft, means coupling the second and third plates to said sleeve, so that said third plate is angularly movable with respect to the second plate about the axis of the sleeve, and a contact breaker assembly carried by the third plate,

the contact breaker assembly including a movable contact carried by an insulating heel which engages the camshaft, and a fixed contact en'gageable by the movable contact, and the arrangement being such that angular movement of the second plate with respect to the first 4 plate about said ofiset axis causes movement of said sleeve, and consequential movement of said third plate and said contact breaker assembly, towards or away from said camshaft so as to adjust the operating gap between said fixed and movable contacts, while angular movement of the'third plate with respect to the second plate, about the axis of said sleeve, movesthe contact breaker assembly angularly with respect to the camshaft, so as to adjust the ignition timing of the d istributor. 2. A distributor as claimed in claim 1 in which the second and third plates are on opposite sides of the first plate.

3. A distributor as claimed in claim 2 in which the sleeve is secured to the third plate and extends through the first plate in spaced relationship thereto, the second plate being slidably mounted on the sleeve and the second and third plates being resiliently urged towards the first plate.

References Cited UNITED STATES PATENTS 2,945,923 7/ 1960, Julian et a1. 200. 31 3,180,948 4/1965 McCarty 200-30 3,202,777 8/ 1965 Scott 200-31 3,207,864 9/1965 Bettoni et al. ZOO-31 3,235,764 2/ 1966 Billin 20o 31 xR ROBERT K. SCHAEFER, Primary Examiner I. R. SCOTT, Assistant Examiner I US. Cl. X.R. 20031 

